Integrated memory devices typically include a memory array area and a peripheral circuitry area. The memory array area constitutes the area in which information or data is stored. The peripheral circuitry area constitutes integrated circuitry which, in part, controls or provides access to the memory array area. One type of integrated memory device is a dynamic random access memory (DRAM) device. DRAMs include, as part of the memory array, plural capacitors which are used to store charges. It is desirable to fabricate integrated circuitry memory devices to have fairly close, comparable, and repeatable capacitance values.
Stacked DRAM capacitors are typically formed from a plurality of layers provided over a substrate by etching at least some of the layers to form a desired capacitor container construction. Capacitors are thereafter formed in the etched containers. To increase the capacitance values of the subsequently formed capacitors, a timed etch is typically conducted to further etch the provided layers after an initial capacitor container definition etch is conducted. Such timed etches can be problematic for a number of reasons. For example, such etches must be carefully monitored and timed to ensure that the etch does not undesirably extend into adjacent integrated device components, which can destroy the circuit. Thus, control of the etches is of major concern. Another problem is that reproducibility of the depth of such etches can be difficult to attain given variations in the processing regimes and materials used to fabricate the capacitor containers. Thus, a need exists for semiconductor processing methods which enable memory devices to be fabricated with predictable and readily reproducible capacitance values.
Another problem associated with the fabrication of integrated memory devices concerns forming electrical connections between conductive lines and substrate active areas in peripheral circuitry areas of the memory array. More specifically, it is sometimes desirable for conductive lines to be electrically connected with substrate active areas which are disposed elevationally lower over a substrate than the respective conductive lines. Typically, the elevational separation between the conductive lines and the substrate active area is due to one or more layers which are interposed between the conductive lines and the corresponding active area to which electrical connection is desired. Often such conductive lines do not typically directly overlie the entire active area with which electrical connection is desired. One prior art solution is to provide a conductive plug of material which extends generally vertically between and connects with the overlying conductive line and only a portion of the active area with which electrical connection is desired. This, however, gives rise to increased resistance and hence lower conductivity as between the conductive line and the elevationally lower substrate active area. Thus, a need exists to provide improved semiconductor processing methods and related integrated circuitry formed thereby with improved conductive connections between elevationally separated conductive lines and substrate active areas.
This invention arose out of concerns associated with forming integrated memory circuitry, particularly DRAM memory devices, with standardized and readily reproducible component values, as well as improving conductive connections between the memory device components.